Photovoltaic devices and methods

Abstract

Photovoltaic devices, and methods of fabricating photovoltaic devices. The photovoltaic devices may include a first electrode, at least one quantum dot layer, at least one semiconductor layer, and a second electrode. The first electrode may include a layer including Cr and one or more silver contacts.

We claim: 
     
       1. A photovoltaic device comprising:
 a first electrode comprising (i) a layer comprising Cr, wherein the layer comprising Cr has a thickness of about 2 nm to about 10 nm, and (ii) at least one contact that (a) comprises Ag, and (b) is arranged on the layer comprising Cr; 
 an active layer having a thickness of at least 350 nm, wherein the active layer comprises—
 (i) at least one first quantum dot layer comprising PbS quantum dots treated with 1,2-ethanedithiol, wherein the layer comprising Cr is arranged between the at least one contact and the at least one first quantum dot layer, and 
 (ii) at least one second quantum dot layer comprising PbS quantum dots treated with tetrabutylammonium iodide; 
 
 at least one semiconductor layer, wherein the at least one second quantum dot layer is arranged between the at least one first quantum dot layer and the at least one semiconductor layer; and 
 a second electrode, wherein the at least one semiconductor layer is arranged between the at least one second quantum dot layer and the second electrode. 
 
     
     
       2. The photovoltaic device of  claim 1 , wherein the active layer comprises 1 or 2 of the at least one first quantum dot layers. 
     
     
       3. The photovoltaic device of  claim 2 , wherein the active layer comprises 1 to 5 of the at least one second quantum dot layers. 
     
     
       4. The photovoltaic device of  claim 1 , wherein the active layer has a thickness of about 380 nm to about 1,500 nm. 
     
     
       5. The photovoltaic device of  claim 1 , wherein the layer comprising Cr has a thickness of about 5 nm. 
     
     
       6. The photovoltaic device of  claim 1 , wherein the photovoltaic device has a fill factor of about 40% to about 50%. 
     
     
       7. The photovoltaic device of  claim 1 , wherein the at least one semiconductor layer is an electron transporting layer. 
     
     
       8. The photovoltaic device of  claim 1 , wherein the at least one semiconductor layer comprises ZnO. 
     
     
       9. The photovoltaic device of  claim 1 , wherein the active layer is in contact with (i) the layer comprising Cr, and (ii) the at least one semiconductor layer.